Treated Fillers, Compositions Containing Same, and Articles Prepared Therefrom

ABSTRACT

The present invention includes a process for producing treated filler that includes (a) treating a slurry that includes untreated filler where the untreated filler has not been previously dried, with a treating composition that includes a treating agent, thereby forming a treated filler slurry, and (b) drying the treated filler slurry to produce treated filler. The treating agent can include at least one of an anhydride, a cyclic imide, and a derivative thereof. The present invention also is directed to treated filler prepared by the process, as well as rubber compounding compositions and tires including the treated filler.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/887,713, filed Oct. 7, 2013, which is hereby incorporated herein itsentirety by reference.

FIELD OF INVENTION

The present invention is related to a process for the preparation oftreated filler, treated filler produced by the process, and compositionsand articles containing such treated filler.

BACKGROUND OF THE INVENTION

The use of silica/silane filler systems to reduce the rolling resistanceand improve the wet traction of passenger car and truck tires is knownin the art. A reduction of rolling resistance results in less fuelconsumption.

The simultaneous improvement of rolling resistance, wear, and traction,known as expanding the “magic triangle”, requires new approaches torubber composite development. Precipitated silica has played a majorrole in the emergence of the green tire, which boasts a largeimprovement in rolling resistance compared to past technologies. Thedirect cross-linking of silica (via coupling) into a highly cross-linkedpolymer matrix, while minimizing interactions between silica particles,is believed to be of vital importance to desirable dynamic mechanicalproperties of rubber used in the production of passenger car and trucktires. It has been noted that in natural rubber (typically used in theproduction of truck tires), the proteins present from natural rubberbiosynthesis can adsorb preferentially to the silica surface,interfering with the in-situ coupling reaction. Increased dumptemperatures, which might improve the coupling efficiency, have alsobeen shown to degrade natural rubber. Thus, there continues to be a needin the rubber industry for improved silica-rubber coupling materials.

Further, it has been found that the incorporation of high surface areafiller materials into rubber compositions can cause an undesirableincrease in viscosity thereby limiting the amount of high surface areamaterial that can be included in the rubber composition due to processproblems. Thus, there is a need to treat such high surface materials(e.g., precipitated silica) with materials which can serve as to renderthe high surface materials more compatible with the polymeric matrixinto which they are being incorporated, improve processing viscosity,and prevent phase separation of the high surface materials from thepolymeric matrix.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a processfor producing treated filler that includes: (a) treating a slurry thatincludes untreated filler, where the untreated filler has not beenpreviously dried, with a treating composition that includes a treatingagent, thereby forming a treated filler slurry; and (b) drying thetreated filler slurry to produce treated filler. The treating agent caninclude at least one of an anhydride, a cyclic imide, and a derivativethereof.

In accordance with the present invention, there is further provided aprocess for producing treated precipitated silica that includes: (a)combining an alkali metal silicate and an acid to form a slurry thatincludes untreated silica, where the untreated silica has not beenpreviously dried; (b) treating said slurry with a treating compositionthat includes a treating agent, thereby forming a treated slurry; and(c) drying said treated slurry to produce treated precipitated silica.The treating agent can include at least one of an anhydride, a cyclicimide, and a derivative thereof.

In accordance with the present invention, there is further provided aprocess for producing a treated precipitated silica that includes: (a)combining an alkali metal silicate and an acid to form an untreatedslurry that includes untreated silica, where the untreated silica hasnot been previously dried; (b) drying the untreated slurry to producedried precipitated silica; (c) forming an aqueous slurry of the driedprecipitated silica with a treating composition that includes a treatingagent, and, optionally, a coupling agent and/or, optionally, anon-coupling agent to form a treated precipitated silica slurry; and (d)drying the treated precipitated silica slurry to produce a dried treatedprecipitated silica. The treating agent can include at least one of ananhydride, a cyclic imide, and a derivative thereof.

In accordance with the present invention, there is also provided treatedfiller prepared by the processes described herein, as well as rubbercompositions such as rubber compounding compositions including thetreated filler, and rubber articles that include the treated filler ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

As previously mentioned, the present invention provides a process forproducing treated filler. The process can include: (a) treating a slurrythat can include untreated filler where the untreated filler has notbeen previously dried, with a treating composition comprising a treatingagent, thereby forming a treated filler slurry; and (b) drying thetreated filler slurry to produce treated filler.

As used herein, with reference to filler (such as, treated and/oruntreated filler), the term “not been previously dried” means fillerthat, prior to the treatment process, has not been dried to a moisturecontent of less than 20 percent by weight. For purposes of the presentinvention, untreated filler does not include filler that has beenpreviously dried to a moisture content of less than 20 percent by weightand then rehydrated.

As used herein, the term “filler” means an inorganic material such as aninorganic oxide that can be used in a polymer composition to improve atleast one property of the polymer. As used herein, the term “slurry”means a mixture including at least filler and water.

As used herein, the articles “a,” “an,” and “the” include pluralreferents unless otherwise expressly and unequivocally limited to onereferent.

Unless otherwise indicated, all ranges or ratios disclosed herein are tobe understood to encompass any and all subranges or subratios subsumedtherein. For example, a stated range or ratio of “1 to 10” should beconsidered to include any and all subranges between (and inclusive of)the minimum value of 1 and the maximum value of 10; that is, allsubranges or subratios beginning with a minimum value of 1 or more andending with a maximum value of 10 or less, such as but not limited to, 1to 6.1, 3.5 to 7.8, and 5.5 to 10.

Other than in the operating examples, or where otherwise indicated, allnumbers expressing quantities of ingredients, reaction conditions, andso forth used in the specification and claims are to be understood asmodified in all instances by the term “about.”

As used herein, molecular weight values of polymers, such as weightaverage molecular weights (Mw) and number average molecular weights(Mn), are determined by gel permeation chromatography using appropriatestandards, such as polystyrene standards.

As used herein, polydispersity index (PDI) values represent a ratio ofthe weight average molecular weight (Mw) to the number average molecularweight (Mn) of the polymer (i.e., Mw/Mn).

As used herein, the term “polymer” means homopolymers (e.g., preparedfrom a single monomer species), copolymers (e.g., prepared from at leasttwo monomer species), and graft polymers.

As used herein, the term “(meth)acrylate” and similar terms, such as“(meth)acrylic acid ester” means methacrylates and/or acrylates. As usedherein, the term “(meth)acrylic acid” means methacrylic acid and/oracrylic acid.

All documents, such as but not limited to issued patents and patentapplications, referred to herein, and unless otherwise indicated, are tobe considered to be “incorporated by reference” in their entirety.

As used herein, recitations of “linear or branched” groups, such aslinear or branched alkyl, are herein understood to include: a methylenegroup or a methyl group; groups that are linear, such as linear C₂-C₃₆alkyl groups; and groups that are appropriately branched, such asbranched C₃-C₃₆ alkyl groups.

As used herein, recitations of “optionally substituted” group, means agroup, including but not limited to, alkyl group, cycloalkyl group,heterocycloalkyl group, aryl group, and/or heteroaryl group, in which atleast one hydrogen thereof has been optionally replaced or substitutedwith a group that is other than hydrogen, such as, but not limited to,halo groups (e.g., F, Cl, I, and Br), hydroxyl groups, ether groups,thiol groups, thio ether groups, carboxylic acid groups, carboxylic acidester groups, phosphoric acid groups, phosphoric acid ester groups,sulfonic acid groups, sulfonic acid ester groups, nitro groups, cyanogroups, hydrocarbyl groups (including, but not limited to: alkyl;alkenyl; alkynyl; cycloalkyl, including poly-fused-ring cycloalkyl andpolycyclocalkyl; heterocycloalkyl; aryl, including hydroxyl substitutedaryl, such as phenol, and including poly-fused-ring aryl; heteroaryl,including poly-fused-ring heteroaryl; and aralkyl groups), and aminegroups, such as N(R₁₁′)(R₁₂′) where R₁₁′ and R₁₂′ are each independentlyselected, with some embodiments, from hydrogen, linear or branchedC₁-C₂₀ alkyl, C₃-C₁₂ cycloakyl, C₃-C₁₂ heterocycloalkyl, aryl, andheteroaryl.

Some compounds that can be used with the method of the present inventioninclude groups and sub groups that can in each case be independentlyselected from hydrocarbyl and/or substituted hydrocarbyl and/orfunctional hydrocarbyl (or hydrocarbyl groups having one or morefunctional groups). As used herein, and in accordance with someembodiments, the term “hydrocarbyl” and similar terms, such as“hydrocarbyl substituent,” means: linear or branched C₁-C₃₆ alkyl (e.g.,linear or branched C₁-C₁₀ alkyl); linear or branched C₂-C₃₆ alkenyl(e.g., linear or branched C₂-C₁₀ alkenyl); linear or branched C₂-C₃₆alkynyl (e.g., linear or branched C₂-C₁₀ alkynyl); C₃-C₁₂ cycloalkyl(e.g., C₃-C₁₀ cycloalkyl); C₅-C₁₈ aryl (including polycyclic arylgroups) (e.g., C₅-C₁₀ aryl); and C₆-C₂₄ aralkyl (e.g., C₆-C₁₀ aralkyl).

Representative alkyl groups include but are not limited to methyl,ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl,pentyl, neopentyl, hexyl, heptyl, octyl, nonyl and decyl. Representativealkenyl groups include but are not limited to vinyl, allyl and propenyl.Representative alkynyl groups include but are not limited to ethynyl, 1propynyl, 2-propynyl, 1-butynyl, and 2-butynyl. Representativecycloalkyl groups include but are not limited to cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl substituents.Representative aralkyl groups include but are not limited to benzyl, andphenethyl.

The term “substituted hydrocarbyl” and similar terms, such as“functional hydrocarbyl” (or hydrocarbyl having at least one functionalgroup) as used herein means a hydrocarbyl group in which at least onehydrogen thereof has been substituted with a group that is other thanhydrogen, such as, but not limited to, halo groups, hydroxyl groups,ether groups, thiol groups, thio ether groups, carboxylic acid groups,carboxylic acid ester groups, phosphoric acid groups, phosphoric acidester groups, sulfonic acid groups, sulfonic acid ester groups, nitrogroups, cyano groups, hydrocarbyl groups (e.g., alkyl, alkenyl, alkynyl,cycloalkyl, aryl, and aralkyl groups), heterocycloalkyl groups,heteroaryl groups, and amine groups, such as —N(R₁₁′)(R₁₂′) where R₁₁′and R₁₂′ are each independently selected from hydrogen, hydrocarbyl andsubstituted hydrocarbyl.

The term “alkyl” as used herein, in accordance with some embodiments,means linear or branched alkyl, such as but not limited to, linear orbranched C₁-C₂₅ alkyl, or linear or branched C₁-C₁₀ alkyl, or linear orbranched C₂-C₁₀ alkyl. Examples of alkyl groups from which the variousalkyl groups of the present invention can be selected from, include, butare not limited to, those recited previously herein. Alkyl groups of thevarious compounds of the present invention can, with some embodiments,include one or more unsaturated linkages selected from —CH═CH— groupsand/or one or more —C≡C— groups, provided the alkyl group is free of twoor more conjugated unsaturated linkages. With some embodiments, thealkyl groups are free of unsaturated linkages, such as CH—CH groups and—C≡C— groups.

The term “cycloalkl” as used herein, in accordance with someembodiments, means groups that are appropriately cyclic, such as but notlimited to, C₃-C₁₂ cycloalkyl (including, but not limited to, cyclicC₅-C₇ alkyl) groups. Examples of cycloalkyl groups include, but are notlimited to, those recited previously herein. The term “cycloalkyl” asused herein in accordance with some embodiments also includes: bridgedring polycycloalkyl groups (or bridged ring polycyclic alkyl groups),such as but not limited to, bicyclo[2.2.1]heptyl (or norbornyl) andbicyclo[2.2.2]octyl; and fused ring polycycloalkyl groups (or fused ringpolycyclic alkyl groups), such as, but not limited to,octahydro-1H-indenyl, and decahydronaphthalenyl.

The term “heterocycloalkyl” as used herein, in accordance with someembodiments, means groups that are appropriately cyclic (having at leastone heteroatom in the cyclic ring), such as but not limited to, C₃-C₁₂heterocycloalkyl groups or C₅-C₇ heterocycloalkyl groups, and which haveat least one hetero atom in the cyclic ring, such as, but not limitedto, O, S, N, P, and combinations thereof. Examples of heterocycloalkylgroups include, but are not limited to, imidazolyl, tetrahydrofuranyl,tetrahydropyranyl, and piperidinyl. The term “heterocycloalkyl” as usedherein, in accordance with some embodiments, also includes: bridged ringpolycyclic heterocycloalkyl groups, such as but not limited to,7-oxabicyclo[2.2.1]heptanyl; and fused ring polycyclic heterocycloalkylgroups, such as but not limited to, octahydrocyclopenta[b]pyranyl, andoctahydro 1H isochromenyl.

As used herein, and in accordance with some embodiments, the term “aryl”includes C₅-C₁₈ aryl, such as C₅-C₁₀ aryl (and includes polycyclic arylgroups, including polycyclic fused ring aryl groups). Representativearyl groups include, but are not limited to, phenyl, naphthyl,anthracynyl, and triptycenyl.

The term “heteroaryl,” as used herein, in accordance with someembodiments, means aryl groups having at least one heteroatom in thering, and includes but is not limited to C₅-C₁₈ heteroaryl, such as butnot limited to C₅-C₁₀ heteroaryl (including fused ring polycyclicheteroaryl groups) and means an aryl group having at least one heteroatom in the aromatic ring, or in at least one aromatic ring in the caseof a fused ring polycyclic heteroaryl group. Examples of heteroarylgroups include, but are not limited to, furanyl, pyranyl, pyridinyl,isoquinoline, and pyrimidinyl.

As used herein, the term “fused ring polycyclic-aryl-alkyl group” andsimilar terms such as, fused ring polycyclic-alkyl-aryl group, fusedring polycyclo-aryl-alkyl group, and fused ring polycyclo-alkyl-arylgroup means a fused ring polycyclic group that includes at least onearyl ring and at least one cycloalkyl ring that are fused together toform a fused ring structure. For purposes of non-limiting illustration,examples of fused ring polycyclic-aryl-alkyl groups include, but are notlimited to indenyl, 9H-flourenyl, cyclopentanaphthenyl, and indacenyl.

The term “aralkyl” as used herein, and in accordance with someembodiments, includes but is not limited to C₆-C₂₄ aralkyl, such as butnot limited to C₆-C₁₀ aralkyl, and means an aryl group substituted withan alkyl group. Examples of aralkyl groups include, but are not limitedto, those recited previously herein.

Suitable untreated fillers for use in process of the present inventioncan include a wide variety of materials known to one having ordinaryskill in the art. Non-limiting examples can include inorganic oxidessuch as inorganic particulate and amorphous solid materials whichpossess either oxygen (chemisorbed or covalently bonded) or hydroxyl(bound or free) at an exposed surface, such as but not limited to oxidesof the metals in Periods 2, 3, 4, 5 and 6 of Groups Ib, IIb, IIIa, IIIb,IVa, IVb (except carbon), Va, VIa, VIIa and VIII of the Periodic Tableof the Elements in Advanced Inorganic Chemistry: A Comprehensive Text byF. Albert Cotton et al, Fourth Edition, John Wiley and Sons, 1980.Non-limiting examples of suitable inorganic oxides can include but arenot limited to aluminum silicates, silica such as silica gel, colloidalsilica, precipitated silica, and mixtures thereof.

The inorganic oxide can be silica with some embodiments. For example, incertain embodiments, the inorganic oxide can include precipitatedsilica, colloidal silica, and mixtures thereof. The silica can have anaverage ultimate particle size of less than 0.1 micron, or greater than0.001 micron, or from 0.01 to 0.05 micron, or from 0.015 to 0.02 micron,as measured by electron microscope. Further, the silica can have asurface area of from 25 to 1000 square meters per gram, such as from 75to 250 square meters per gram, or from 100 to 200 square meters pergram, as determined by the Brunauer, Emmett, and Teller (BET) method inaccordance with ASTM D1993-91. With some embodiments, the filler isprecipitated silica.

As previously mentioned, the untreated filler slurry is treated with atreating composition that can include a treating agent. In certainembodiments, the treating agent can act as a coupling agent. The term“coupling agent” as used herein means a material that binds (ionicallyor covalently) to (i) groups present on the surface of the fillerparticle (such as on the silica surface), as well as to (ii) functionalgroups present on the component(s) of the polymeric matrix into whichthe filler is incorporated. Thus, the filler particles can be “coupled”to the components in the polymeric matrix.

Alternatively, with some embodiments, the treating agent can act as anon-coupling agent. The term “non-coupling agent” as used herein means amaterial that serves to compatibilize the treated filler with thepolymeric composition in which the treated filler ultimately is used.That is, the non-coupling agent can affect the free surface energy ofthe treated filler particles to make the treated filler particles have asurface energy similar to that of the polymeric composition. Thisfacilitates incorporation of the treated filler into the polymericcomposition, and can serve to improve (such as, decrease) mix viscosityof the composition. It should be noted that non-coupling agents are notexpected to couple with the rubber matrix beyond Van der Waalinteractions. As used herein, the term “non-coupling agent” can be usedinterchangeably with “compatibilizer”.

It should be noted that many of the treatment agents may simultaneouslyfunction as both a coupling agent and a non-couplingagent/compatibilizer.

The treating agent, with some embodiments of the present invention, caninclude at least one of an anhydride, a cyclic imide, and a derivativethereof. In one embodiment, the anhydride can be a cyclic anhydride.Non-limiting examples of suitable anhydrides, cyclic imides, andderivatives thereof include benzoic anhydride, acetic anhydride, maleicanhydride, succinic anhydride, maleimide, succinimide, and/orderivatives thereof. As used herein, “derivatives” refers to salts, ringopened products (including carboxylic acid esters, di-carboxylic acidesters, and di-carboxylic acids thereof), and substituted products ofanhydrides and cyclic imides. In certain embodiments, the ring openedproducts can be formed through a hydrolysis reaction. As used herein,the term “substituted products” with regard to the treating agents, suchas anhydrides and cyclic imides, means that such compounds include oneor more substituents covalently bonded thereto, such as, but not limitedto, those substituents and groups described previously herein withregard to substituted hydrocarbyls and, optionally substituted groups.With some of these embodiments, the anhydrides and/or cyclic imides aresubstituted with a group that includes a carbon-carbon double bond.Non-limiting examples of groups that include carbon-carbon double bondsinclude alkene, allyl, alkenyl, vinyl, and combinations thereof.

With some embodiments, the treating agent includes at least one ofmaleimide, succinimide, and fused ring succinimide that can each berepresented by the following formulas (A), (B), and (C):

where R* in each case is independently hydrogen, or linear or branchedC₁ to C₁₀ hydrocarbyls. With reference to formula (C), ring-A canselected from, for example, cycloalkyl, fused ring polycycloalkyl,heterocycloalkyl, fused ring polycyclicheterocycloalkyl, aryl, fusedring polycyclicaryl, heteroaryl, fused ring polycyclicheteroaryl, andfused ring polycyclic-aryl-alkyl, which can each independently beoptionally substituted. With some embodiments, ring-A is substitutedwith at least one group having a carbon-carbon double bond. With someembodiments, ring-A is an optionally substituted cyclohexane ring, or anoptionally substituted benzene ring.

With some other embodiments, the maleimide, such as represented byformula (A), is prepared by reacting maleic anhydride with an aminefollowed by dehydration in accordance with art-recognized methods. Withsome further embodiments, the succinimide, such as represented byformula (B), is prepared by reacting succinic anhydride with an aminefollowed by dehydration in accordance with art-recognized methods. Withsome embodiments, the fused ring succinimide, such as represented byformula (C), is prepared by reacting fused ring succinic anhydride withan amine followed by dehydration in accordance with art-recognizedmethods.

With some embodiments, the treating agent includes a cyclic anhydridethat can be represented by the following formula (D):

With reference to formula (D), ring-A is as described previously hereinwith reference to ring-A of formula (C).

With some embodiments, in addition to the treatment agents listed above,the treating composition can further include a first or additionalcoupling agent that is different than the treating agent. In certainembodiments, the coupling agent can include any of a variety oforganosilanes. Examples of suitable organosilanes that can be used withsome embodiments of the present invention include those represented byFormula (I):

(R₁)_(a)(R₂)_(b)SiX_(4-a-b)  (I).

With reference to Formula (I), R₁ is independently for each “a”, ahydrocarbyl group having 1 to 36 carbon atoms and a functional group.The functional group of the hydrocarbyl group is vinyl, allyl, hexenyl,epoxy (oxirane), glycidoxy, (meth)acryloxy, sulfide, isocyanato (—NCO),polysulfide, mercapto, or halogen. With reference to Formula (I), R₂ isindependently for each “b” a hydrocarbyl group having from 1 to 36carbon atoms or hydrogen. X of Formula (I) is independently halogen oralkoxy having 1 to 36 carbon atoms; subscript “a” is 0, 1, 2, or 3;subscript “b” is 0, 1, or 2; (a+b) is 1, 2, or 3. With some embodiments,there is the proviso that when b is 1, (a+b) is 2 or 3. With somefurther embodiments of the present invention, the treating compositionfurther a coupling agent represented by Formula (I), in which X isalkoxy; a is 1; b is 0; and the functional group of the hydrocarbyl ofR₁, is halogen.

Examples of halo-functional organosilanes, such as those represented byFormula (I), include, but are not limited to,(4-chloromethyl-phenyl)trimethoxysilane,(4-chloromethyl-phenyl)triethoxysilane,[2-(4-chloromethyl-phenyl)-ethyl]trimethoxysilane,[2-(4-chloromethyl-phenyl)-ethyl]triethoxysilane,(3-chloro-propenyl)-trimethoxysilane,(3-chloro-propenyl)-triethoxysilane, (3-chloro-propyl)-triethoxysilane,(3-chloro-propyl)-trimethoxysilane, trimethoxy-(2-p-tolyl-ethyl)silaneand/or triethoxy-(2-p-tolyl-ethyl)silane.

In certain embodiments, the additional coupling agent can be present inthe slurry in an amount ranging from 0.25 to 30.0 weight percent, suchas 1 to 15 weight percent, or 5 to 10 weight percent based on the totalmass of SiO₂ which has been precipitated.

In certain embodiments, the treating composition useful in the processof the present invention also can further include a sulfur-containingorganosilane that is different from the aforementioned optionalorganosilane coupling agents, such as represented by Formula (I).Non-limiting examples of such materials can include, but are not limitedto, organosilanes represented by the following Formula (II):

(R₃)_(c)(R₄)_(d)SiY_(4-c-d)  (II).

With reference to Formula (II), R₃ independently for each “c” can be ahydrocarbyl group having 1 to 12 carbon atoms and a functional group.The functional group can be sulfide, polysulfide or mercapto. Withreference to Formula (II), R₄ independently for each “d” can be ahydrocarbyl group having from 1 to 18 carbon atoms or hydrogen. Each Yeach can independently be halogen or an alkoxy group having 1 to 12carbon atoms. Subscript “c” can be 0, 1, 2, or 3; subscript “b” can be0, 1, or 2; and c+d can be 1, 2, or 3. With some embodiments, there isthe proviso that when b is 1 then a+b is 2 or 3. The R₃ and R₄ groups ofFormula (II) can be selected such that they can react with the polymericcomposition in which the treated filler can be incorporated.Additionally, the sulfur-containing organosilane can includebis(alkoxysilylalkyl)polysulfides represented by following Formula(III):

Z′-alk-S_(n′)-alk-Z′  (III).

With reference to Formula (III), “alk” represents a divalent hydrocarbonradical having from 1 to 18 carbon atoms; n′ is an integer from 2 to 12;and Z′ is:

in which R₅ is independently an alkyl group having from 1 to 4 carbonatoms or phenyl, and each R₆ is independently an alkoxy group havingfrom 1 to 8 carbon atoms, a cycloalkoxy group with from 5 to 8 carbonatoms, or a straight or branched chain alkylmercapto group with from 1to 8 carbon atoms. The R₅ and R₆ groups can be the same or different.Also, the divalent alk group can be straight or branched chain, asaturated or unsaturated aliphatic hydrocarbon group or a cyclichydrocarbon group. Non-limiting examples ofbis(alkoxysilylalkyl)-polysulfides can includebis(2-trialkoxysilylethyl)-polysulfides in which the trialkoxy group canbe trimethoxy, triethoxy, tri(methylethoxy), tripropoxy, tributoxy, etc.up to trioctyloxy and the polysulfide can be either di-, tri-, tetra-,penta-, or hexasulfide, or mixtures thereof. Further non-limitingexamples can include the corresponding bis(3-trialkoxysilylpropyl)-,bis(3-trialkoxysilylisobutyl), -bis(4-trialkoxysilylbutyl)-, etc. up tobis(6-trialkoxysilyl-hexyl)-polysulfides. Further non-limiting examplesof bis(alkoxysilylalkyl)-polysulfides are described in U.S. Pat. No.3,873,489, column 6, lines 5-55, and in U.S. Pat. No. 5,580,919, atcolumn 11, lines 11-41. Further non-limiting examples of such compoundscan include: 3,3′bis(trimethoxysilylpropyl)disulfide,

-   3,3′-bis(triethoxysilylpropyl)tetrasulfide,-   3,3′-bis(trimethoxysilylpropyl)tetrasulfide,    2,2′-bis(triethoxysilylethyl)tetrasulfide,-   3,3′-bis(trimethoxysilylpropyl)trisulfide,    3,3′-bis(triethoxysilylpropyl)trisulfide,-   3,3′-bis(tributoxysilylpropyl)disulfide,    3,3′-bis(trimethoxysilylpropyl)hexasulfide, and-   3,3′-bis(trioctoxysilylpropyl)tetrasulfide and mixtures thereof.    The sulfur-containing organosilane also can be a    mercaptoorganometallic compound represented by the following Formula    (IV):

With reference to Formula (IV), M′ is silicon, L is halogen or —OR₈, Qis hydrogen, C₁-C₁₂ alkyl, or halo-substituted C₁-C₁₂ alkyl, R₇ isC₁-C₁₂ alkylene, R₈ is C₁-C₁₂ alkyl or alkoxyalkyl containing from 2 to12 carbon atoms, the halogen or (halo) groups being chloro, bromo, iodoor fluoro, and n is 1, 2 or 3. In a non-limiting embodiment,mercaptoorganometallic reactants having two mercapto groups can be used.

Non-limiting examples of useful mercaptoorganometallic compounds includebut are not limited to mercaptomethyltrimethoxysilane,mercaptoethyltrimethoxysilane, mercaptopropyltrimethoxysilane,mercaptomethyltriethoxysilane, mercaptoethyltripropoxysilane,mercaptopropyltriethoxysilane, (mercaptomethyl)dimethylethoxysilane,(mercaptomethyl)methyldiethoxysilane,3-mercaptopropyl-methyldimethoxysilane, and mixtures thereof.

With some embodiments of the present invention, the sulfur-containingorganosilane can be a mercaptoorganometallic compound such as amercaptosilane different from the organosilane used in the treatingcomposition of step (a), for example, mercaptopropyltrimethoxysilaneand/or mercaptomethyltriethoxysilane.

Also, it is contemplated that the sulfur-containing organosilanerepresented by Formula (IV), which is different from the aforementionedorganosilane coupling agent represented by Formula (I), that can be usedin step (a) of the process of the present invention, can be amercaptoorganometallic compound in which the mercapto group is blocked,i.e., the mercapto hydrogen atom is replaced by another group. Blockedmercaptoorganometallic compounds can have an unsaturated heteroatom orcarbon bound directly to sulfur via a single bond. Non-limiting examplesof specific blocking groups can include thiocarboxylate ester,dithiocarbamate ester, thiosulfonate ester, thiosulfate ester,thiophosphate ester, thiophosphonate ester, and thiophosphinate ester.

With some non-limiting embodiments, in which a blockedmercaptoorganometallic compound is used as an optional couplingmaterial, a deblocking agent can be added to the polymeric compoundmixture to deblock the blocked mercaptoorganometallic compound. Withsome non-limiting embodiments in which water and/or alcohol are presentin the mixture, a catalyst, such as, tertiary amines, Lewis acids orthiols, can be used to initiate and promote the loss of the blockinggroup by hydrolysis or alcoholysis to liberate the correspondingmercaptoorganometallic compounds. Non-limiting examples of blockedmercaptosilanes can include but are not limited to2-triethoxysilyl-1-ethyl thioacetate, 3-trimethoxy-silyl-1-propylthiooctoate, bis-(3-triethoxysilyl-1-propyl)-methyldithiophosphonate,3-triethoxysilyl-1-propyldimethylthiophosphinate,3-triethoxysilyl-1-propylmethylthiosulfate,3-triethoxysilyl-1-propyltoluenethiosulfonate, and mixtures thereof.

The amount of these optional sulfur-containing organosilanes can varywidely and can depend upon the particular material selected. Forexample, the amount of these optional sulfur-containing organosilanescan be greater than 0.1% based on the weight of untreated filler, suchas from 0.5% to 25% based on the weight of untreated filler, or from 1%to 20%, or from 2% to 15%.

In certain embodiments, the treating composition can further include ahalo-functional organosilane, which includes a monomeric, dimeric,oligomeric and/or or polymeric compound possessing halogen functionalityand alkanedioxysilyl functionality derived from: (i)polyhydroxyl-containing compounds in which the alkanedioxy group iscovalently bonded to a single Si atom through Si—O bonds to form a ring;and/or (ii) the alkanedioxy groups are covalently bonded to at least twoSi atoms through Si—O bonds to form a dimer, oligomer, or polymer inwhich adjacent silyl units are bonded to each other through bridgedalkanealkoxy structures. Such halo-functional organosilanes aredescribed in detail in United States Published Patent Application No.2011/0003922A1, published Jan. 6, 2011, at paragraphs [0020] to [0057],the cited portions of which are incorporated by reference herein.

Mixtures of any of the aforementioned coupling agents can be used in theprocess of the present invention.

With some embodiments, in addition to treating agent describedpreviously herein, the treating composition can optionally furtherinclude a first or additional non-coupling agent/compatibilizer that isdifferent from the treating agent. The additional non-couplingagent/compatibilizer can be selected from saturated biopolymers,saturated fatty acids, saturated organic acids, saturated polymeremulsions, saturated polymer coating composition, and mixtures thereof.The additional non-coupling agent/compatibilizer can alternatively orfurther include a surfactant selected from anionic, nonionic andamphoteric surfactants, and mixtures thereof.

The additional non-coupling agent/compatibilizer can, with someembodiments, be present in an amount of from greater than 1% to 25% byweight based on the total weight of untreated filler, such as the totalmass of SiO₂ which has been precipitated. For example, the additionalnon-coupling agent/compatibilizer can be chosen from salts of fattyacids, alkyl sarcosinates, salts of alkyl sarcosinates, and mixturesthereof. Specific non-limiting examples of such can be found in U.S.Pat. No. 7,569,107 at column 5, line 9, to column 7, line 21, the citedportions of which are incorporated by reference herein. With someembodiments of the present invention, the additional non-couplingagent/compatibilizer can include one or more anionic surfactantsselected from sodium stearate, ammonium stearate, ammonium cocoate,sodium laurate, sodium cocyl sarcosinate, sodium lauroyl sarconsinate,sodium soap of tallow, sodium soap of coconut, sodium myristoylsarcosinate, and/or stearoyl sarcosine acid.

The additional non-coupling agent/compatibilizer, with some embodiments,is present in an amount of from greater than 1% up to and including 25%by weight, for example 2.0% to 20.0%, or 4% to 15%, or 5% to 12% byweight based on the total weight of the untreated filler, such as totalmass of SiO₂ that has been precipitated.

With some embodiments, the additional non-coupling agent/compatibilizercan be a non-coupling organosilane. Non-limiting examples ofnon-coupling silanes from which the additional non-couplingagent/compatibilizer can selected, with some embodiments, includeoctadecyltriethoxysilane, octadecyltrichlorosilane,octadecyltrimethoxysilane, propyltriethoxysilane,propyltrimethoxysilane, propyltrichlorosilane, n-octyltrimethoxysilane,n-octyltriethoxysilane, n-octyltrichlorosilane, n-hexyltrimethoxysilane,n-hexyltriethoxysilane, and/or n-hexyltrichlorosilane.

It should be understood that for purposes of the present invention, anyof the aforementioned organosilanes, including the organosilane havingthe structure (I) as described above, can, with some embodiments,include partial hydrolyzates thereof.

The untreated filler used with various embodiments of the presentinvention, can be prepared using any of a variety of art-recognizedmethods. For example, in the instance where the untreated filler isuntreated silica, the untreated filler can prepared by combining anaqueous solution of soluble metal silicate with acid solution to form asilica slurry; the silica slurry optionally can be aged; acid or basecan be added to the optionally aged silica slurry to adjust pH of theslurry; the silica slurry can be filtered, optionally washed, and thendried using art-recognized techniques. A treatment composition such asany of those described above can be added at any step in theabove-described process prior to drying in accordance with variousembodiments of the present invention.

With some alternative embodiments, the present invention is directed toa process for producing a treated precipitated silica that includes:

(a) combining alkali metal silicate and acid to form an untreatedslurry;

(b) optionally, treating the untreated slurry with the treatingcomposition including the treating agent to form a treated slurry;

(c) drying the untreated slurry of (a), or drying the treated slurry of(b), to in each case produce dried precipitated silica;

(d) forming an aqueous slurry of the dried precipitated silica of step(c) with the treatment composition that includes the treating agent toform a treated silica slurry; and

(e) drying the treated silica slurry to produce a dried treatedprecipitated silica.

With some embodiments and with reference to the above-summarizedprocess, whether or not a treatment composition has been included in theuntreated slurry prior to drying, an aqueous slurry of the driedprecipitated silica (treated or untreated) can be prepared, and atreatment composition can then be added to form a treated slurry ofprecipitated silica, which is subsequently re-dried to produce a treatedprecipitated silica.

Additionally the precipitated silica of any of the foregoing embodimentscan be included in a polymer blend and compounded with a treatmentcomposition as described previously herein.

Further detailed descriptions of the process for forming the treatedsilica can be found herein below in the Examples.

Suitable metal silicates that can be used with some embodiments of thepresent invention can include a wide variety of materials known in theart. Non-limiting examples can include but are not limited to aluminasilicate, lithium silicate, sodium silicate, potassium silicate, andmixtures thereof. The metal silicate can be represented by the followingstructural formula: M₂O(SiO₂)x wherein M can be alumina, lithium, sodiumor, potassium, and x can range from 0.1 to 4.

Suitable acids that can be used with some embodiments of the presentinvention can be selected from a wide variety of acids known in the art.Non-limiting examples can include but are not limited to mineral acids,organic acids, carbon dioxide, sulfuric acid, and mixtures thereof.

The treated fillers which are prepared by the processes of the presentinvention are suitable for inclusion in organic polymeric compositions.The treated filler materials prepared by the process of the presentinvention are useful with some embodiments in rubber compoundingcompositions, such as rubber compositions used in the manufacture oftires and tire components such as tire treads.

Polymeric compositions into which treated fillers prepared accordingwith the method of the present invention include, but are not limitedto, those described in Kirk Othmer Encyclopedia of Chemical Technology,Fourth Edition, 1996, Volume 19, pp 881-904, which description is hereinincorporated by reference. The treated filler prepared in accordancewith various embodiments of the present invention can be admixed withthe polymer or the polymerizable components thereof while the physicalform of the polymer or polymerizable components is in any liquid orcompoundable form such as a solution, suspension, latex, dispersion, andthe like. The polymeric compositions containing the treated filler ofthe present invention can be milled, mixed, molded and, optionally,cured, by any manner known in the art, to form a polymeric article.Classes of polymers can include but are not limited to thermoplastic andthermosetting resins, rubber compounds and other polymers havingelastomeric properties.

The aforementioned polymers can include, for example, alkyd resins, oilmodified alkyd resins, unsaturated polyesters, natural oils (e.g.,linseed, tung, soybean), epoxides, nylons, thermoplastic polyester(e.g., polyethyleneterephthalate, polybutyleneterephthalate),polycarbonates, i.e., thermoplastic and thermoset, polyethylenes,polybutylenes, polystyrenes, polypropylenes, ethylene propylene co- andterpolymers, acrylics (homopolymer and copolymers of acrylic acid,acrylates, mathacrylates, acrylamides, their salts, hydrohalides, etc.),phenolic resins, polyoxymethylene (homopolymers and copolymers),polyurethanes, polysulfones, polysulfide rubbers, nitrocelluloses, vinylbutyrates, vinyls (vinyl chloride and/or vinyl acetate containingpolymers), ethyl cellulose, the cellulose acetates and butyrates,viscose rayon, shellac, waxes, ethylene copolymers (e.g., ethylene-vinylacetate copolymers, ethylene-acrylic acid copolymers, ethyleneacrylatecopolymers), organic rubbers (both synthetic and natural rubbers) andthe like.

The amount of treated filler that can be used in a polymeric compositioncan vary widely depending upon the polymeric composition and the desiredproperties of the article to be formed from the polymeric composition.For example, the amount of treated filler present in the polymericcomposition can range from 5 up to 70 weight %, based on the totalweight of the polymeric composition.

With some non-limiting embodiments, the polymeric composition caninclude an organic rubber. Non-limiting examples of such rubbers caninclude but are not limited to natural rubber; those formed from thehomopolymerization of butadiene and its homologues and derivatives suchas: cis-1,4-polyisoprene; 3,4-polyisoprene; cis-1,4-polybutadiene;trans-1,4-polybutadiene; 1,2-polybutadiene; and those formed from thecopolymerization of butadiene and its homologues and derivatives withone or more copolymerizable monomers containing ethylenic unsaturationsuch as styrene and its derivatives, vinyl-pyridine and its derivatives,acrylonitrile, isobutylene and alkyl-substituted acrylates such asmethyl methacrylate. Further non-limiting examples can includestyrene-butadiene copolymer rubber composed of various percentages ofstyrene and butadiene and employing the various isomers of butadiene asdesired (hereinafter “SBR”); terpolymers of styrene, isoprene andbutadiene polymers, and their various isomers; acrylonitrile-basedcopolymer and terpolymer rubber compositions; and isobutylene-basedrubber compositions; or a mixture thereof, as described in, for example,U.S. Pat. Nos. 4,530,959; 4,616,065; 4,748,199; 4,866,131; 4,894,420;4,925,894; 5,082,901; and 5,162,409.

Non-limiting examples of suitable organic polymers can includecopolymers of ethylene with other high alpha olefins such as propylene,butene-1 and pentene-1 and a diene monomer. The organic polymers can beblock, random, or sequential and can be prepared by methods known in theart such as but not limited to emulsion (e.g. e-SBR) or solutionpolymerization processes (e.g., s-SBR). Further non-limiting examples ofpolymers for use in the present invention can include those which arepartially or fully functionalized including coupled or star-branchedpolymers. Additional non-limiting examples of functionalized organicrubbers can include polychloroprene, chlorobutyl and bromobutyl rubberas well as brominated isobutylene-co-paramethylstyrene rubber. In anon-limiting embodiment, the organic rubber can be polybutadiene, s-SBRand mixtures thereof.

The polymeric composition can be a curable rubber. The term “curablerubber” is intended to include natural rubber and its various raw andreclaimed forms as well as various synthetic rubbers. In alternatenon-limiting embodiments, curable rubber can include combinations of SBRand butadiene rubber (BR), SBR, BR and natural rubber and any othercombinations of materials previously disclosed as organic rubbers. Inthe description of this invention, the terms “rubber”, “elastomer” and“rubbery elastomer” can be used interchangeably, unless indicatedotherwise. The terms “rubber composition”, “compounded rubber” and“rubber compound” are used interchangeably to refer to rubber which hasbeen blended or mixed with various ingredients and materials, and suchterms are well-known to those having skill in the rubber mixing orrubber compounding art.

Rubber compositions that include the treated filler produced by theprocess of the present invention and can be used in the manufacture of amyriad of rubber articles, such as for example, a tire at least onecomponent of which, e.g., the tread, comprises the cured rubbercomposition, as well as other rubber articles such as shoe soles, hoses,seals, cable jackets, gaskets, belts, and the like. Rubber compositionscomprising the treated filler produced by the process of the presentinvention are particularly advantageous for use in the manufacture oftire treads exhibiting low rolling resistance and high wear resistance,including when the tire treads are based on natural rubber. Moreover,with some embodiments, lower cure temperatures can be achieved for suchnatural rubber compositions containing the treated filler produced bythe process of the present invention.

The treated filler of the present invention (as a powder, granule,pellet, slurry, aqueous suspension, or solvent suspension) may becombined with base material, i.e., material used in the product to bemanufactured, to form a mixture referred to as a master batch. In themaster batch, the treated filler may be present in higher concentrationthan in the final product. Aliquots of this mixture are typically addedto production-size quantities during mixing operations in order to aidin uniformly dispersing very small amounts of such additives topolymeric compositions, e.g., plastics, rubbers and coatingcompositions.

The treated filler may be combined with emulsion and/or solutionpolymers, e.g., organic rubber comprising solution styrene/butadiene(SBR), polybutadiene rubber, or a mixture thereof, to form a masterbatch. One contemplated embodiment is a master batch comprising acombination of organic rubber, water-immiscible solvent, treated fillerand, optionally, processing oil. Such a product may be supplied by arubber producer to a tire manufacturer. The benefit to the tiremanufacturer of using a master batch is that the treated filler isuniformly dispersed in the rubber, which results in minimizing themixing time to produce the compounded rubber. The master batch cancontain from 10 to 150 parts of treated silica per 100 parts of rubber(phr), or from 20 to 130 phr, or from 30 to 100 phr, or from 50 to 80phr.

The present invention is more particularly described in the followingexamples, which are intended to be illustrative only, since numerousmodifications and variations therein will be apparent to those skilledin the art. Unless otherwise specified, all parts and all percentagesare by weight.

Examples Part 1—Analytical Testing

The silica CTAB surface area values reported in the examples of thisapplication were determined using a CTAB solution and the hereinafterdescribed method. The analysis was performed using a Metrohm 751 Titrinoautomatic titrator, equipped with a Metrohm Interchangeable “Snap-In” 50milliliter burette and a Brinkmann Probe Colorimeter Model PC 910equipped with a 550 nm filter. In addition, a Mettler Toledo HB43 orequivalent was used to determine the 105° C. moisture loss of the silicaand a Fisher Scientific Centrific™ Centrifuge Model 225 was used forseparating the silica and the residual CTAB solution. The excess CTABwas determined by auto titration with a solution of AEROSOL® OT(dioctylsodium sulfosuccinate, available from Cytec Industries, Inc.)until maximum turbidity was attained, which was detected with the probecolorimeter. The maximum turbidity point was taken as corresponding to amillivolt reading of 150. Knowing the quantity of CTAB adsorbed for agiven weight of silica and the space occupied by the CTAB molecule, theexternal specific surface area of the silica was calculated and reportedas square meters per gram on a dry-weight basis.

Solutions required for testing and preparation included a buffer of pH9.6, cetyl [hexadecyl]trimethyl ammonium bromide (CTAB, also known ashexadecyl trimethyl ammonium bromide, technical grade), AEROSOL® OT and1N sodium hydroxide. The buffer solution of pH 9.6 was prepared bydissolving 3.101 g of orthoboric acid (99%; technical grade,crystalline) in a one-liter volumetric flask, containing 500 millilitersof deionized water and 3.708 grams of potassium chloride solids (FisherScientific, Inc., technical grade, crystalline). Using a burette, 36.85milliliters of the 1N sodium hydroxide solution was added. The solutionwas mixed and diluted to volume.

The CTAB solution was prepared using 11.0 g+/−0.005 g of powdered CTABonto a weighing dish. The CTAB powder was transferred to a 2-literbeaker and the weighing dish was rinsed with deionized water.Approximately 700 milliliters of the pH 9.6 buffer solution and 1000milliliters of distilled or deionized water was added to the 2-literbeaker and stirred with a magnetic stir bar. A large watch glass wasplaced on the beaker and the beaker was stirred at room temperatureuntil the CTAB powder was totally dissolved. The solution wastransferred to a 2-liter volumetric flask, rinsing the beaker and stirbar with deionized water. The bubbles were allowed to dissipate, and thesolution diluted to volume with deionized water. A large stir bar wasadded and the solution mixed on a magnetic stirrer for approximately 10hours. The CTAB solution can be used after 24 hours and for only 15days. The AEROSOL® OT solution was prepared using 3.46 g+/−0.005 g,which was placed onto a weighing dish. The AEROSOLS OT on the weighingdish was rinsed into a 2-liter beaker, which contained about 1500milliliter deionized water and a large stir bar. The AEROSOL® OTsolution was dissolved and rinsed into a 2-liter volumetric flask. Thesolution was diluted to the 2-liter volume mark in the volumetric flask.The AEROSOL® OT solution was allowed to age for a minimum of 12 daysprior to use. The shelf life of the AEROSOL® OT solution is 2 monthsfrom the preparation date.

Prior to surface area sample preparation, the pH of the CTAB solutionwas verified and adjusted to a pH of 9.6+/−0.1 using 1N sodium hydroxidesolution. For test calculations a blank sample was prepared andanalyzed. 5 milliliters of the CTAB solution was pipetted and 55milliliters deionized water was added into a 150-milliliter beaker andanalyzed on a Metrohm 751 Titrino automatic titrator. The automatictitrator was programmed for determination of the blank and the sampleswith the following parameters: Measuring point density=2, Signaldrift=20, Equilibrium time=20 seconds, Start volume=0 ml, Stop volume=35ml, and Fixed endpoint=150 mV. The burette tip and the colorimeter probewere placed just below the surface of the solution, positioned such thatthe tip and the photo probe path length were completely submerged. Boththe tip and photo probe were essentially equidistant from the bottom ofthe beaker and not touching one another. With minimum stirring (settingof 1 on the Metrohm 728 stirrer) the colorimeter was set to 100% T priorto every blank and sample determination and titration was initiated withthe AEROSOLS OT solution. The end point was recorded as the volume (ml)of titrant at 150 mV.

For test sample preparation, approximately 0.30 grams of powdered silicawas weighed into a 50-milliliter container containing a stir bar.Granulated silica samples, were riffled (prior to grinding and weighing)to obtain a representative sub-sample. A coffee mill style grinder wasused to grind granulated materials. Then 30 milliliters of the pHadjusted CTAB solution was pipetted into the sample container containingthe 0.30 grams of powdered silica. The silica and CTAB solution was thenmixed on a stirrer for 35 minutes. When mixing was completed, the silicaand CTAB solution were centrifuged for 20 minutes to separate the silicaand excess CTAB solution. When centrifuging was completed, the CTABsolution was pipetted into a clean container minus the separated solids,referred to as the “centrifugate”. For sample analysis, 50 millilitersof deionized water was placed into a 150-milliliter beaker containing astir bar. Then 10 milliliters of the sample centrifugate was pipettedfor analysis into the same beaker. The sample was analyzed using thesame technique and programmed procedure as used for the blank solution.

The BET surface area values reported in the examples of this applicationwere determined in accordance with the Brunauer-Emmet-Teller (BET)method in accordance with ASTM D1993-03. The BET surface area wasdetermined by fitting five relative-pressure points from a nitrogensorption isotherm measurement made with a Micromeritics TriStar 3000™instrument. A flow Prep060™ station provided heat and a continuous gasflow to prepare samples for analysis. Prior to nitrogen sorption, thesilica samples were dried by heating to a temperature of 160° C. inflowing nitrogen (P5 grade) for at least one (1) hour.

The weight percent carbon (C) and sulfur (S) values reported in theexamples of this application were determined using a Flash 2000elemental analyzer. This system was set up to monitor carbon and sulfur.Typical parameters included: the combustion furnace being set to 950°C., the GC oven temperature being set to 65° C., the carrier helium gasflow rate being set to 140 mL/min, the reference helium gas flow ratebeing set to 100 mL/min, the oxygen flow rate being set to 250 mL/minand oxygen injection time of 5 seconds. For a given run, calibrationstandards, samples, and controls were typically run. To each 8-10 mg ofvanadium pentoxide (V205) was added. The sample size was between 2-4 mgand they were sealed in tin capsules prior to analysis. If the controlstandard was not within ±10% relative of the known accepted value or thesamples run in duplicate do not match (±5% relative), the entire samplerun was reanalyzed.

The weight percent mercaptan (SH) values reported in the examples ofthis application were determined using a back-titration method. Thesamples were dispersed in 75 mL of 2-Propanol, followed by addition ofexcess 0.1N Iodine solution. The test solution was then flushed withnitrogen, capped and allowed to stir for 15 minutes. The unreactediodine was subsequently back-titrated with standardized 0.05N sodiumthiosulfate to a colorless end point.

Part 2—Compound Testing Procedures and Equipment

Test Methods and Equipment Used Rubber Property Test Method EquipmentProcess ASTM D1646-00 Alpha Technologies Mooney MV2000 Viscometer CureASTM D2084-01 Monsanto MDR2000 Stress/Strain ASTM D412-98A Instron4204/4400R Density ISO 2787-2008 Mettler Toledo XS203S (water) withdensity kit Rebound ISO 4662 Zwick 5109 Hardness ASTM D2240-02, Shore AZwick Digital Durometer Dynamic ASTM D5992-96, Ares-G2 RheometerProperties parallel plate geometry Filler ISO 11345, method B, OptigradeAB DisperGrader Dispersion 100X Magnification, 1000 NT+ Ref. Lib. G(CB/Silica) Abrasion ASTM D-5963-97A Hampden Model APH-40 Resistance DINAbrasion Tester

Example A

Precipitated silica slurry was produced through the sulfuric acidneutralization of a sodium silicate. This slurry was filtered and washedto produce a filter cake. This filter cake was mixed with a Cowles bladeto form a solid in liquid suspension. The percent solids of thisliquefied slurry was determined and used in Equation 1 along with thevalues shown for the respective treatment materials in Table 1 todetermine the amount of treatment applied for the respective examplesshown in Table 1.

Treatment (g)=Weight of slurry (g)*solids (wt. %/100)*0.75%.  Equation1:

TABLE 1 Treatment Amount of anhydride Example Type of anhydride (wt. %)CE-A.1 None None (Comparative) A.2 Succinic anhydride 0.75 A.3 Allylsuccinic anhydride 0.75

The respective treatment materials were added and mixed with a Cowlesblade for a minimum of 10 minutes. This treated slurry was than dried ina Niro spray drier (inlet temperature about 400° C.; outlet temperatureabout 105° C.). The moisture of the spray dried powders was in the 4-7weight percent range. The spray dried powders were granulated using anAlexanderwerk WP 120×40 Roller Compactor using a feed screw speed of54.5 rpm, a roll compactor speed of 4.6 rpm, a crusher speed of 55.0rpm, a screen gap of 1.5 mm, a vacuum pressure of 26.2 BAR and at agranulation pressure of 20 BAR. The resulting physical and chemicalproperties are shown in Table 2. The detectable carbon content onExamples A.2 and A.3 is indicative of the anhydride treatment remainingon the silica.

TABLE 2 Physical and Chemical Properties CTAB, BET, C, Example TreatmentDescription m²/g m²/g wt. % CE-A.1 None 133.0 134.0 0.0 A.2 0.75 wt %succinic anhydride 129.0 124.0 0.35 A.3 0.75 wt % allyl succinicanhydride 127.0 120.0 0.48

Model Passenger Tread Formulation I

The model passenger tread formulations used to compare the Example Ainventive and comparative silicas is shown in Table 3. A 1.89 liter (L)Kobelco Stewart Bolling Inc. mixer (Model “00”) equipped with 4 wingrotors and a Farrel 12 inch two-roll rubber mill were used for mixingthe ingredients following ASTM D3182-89.

The formulations were mixed using one non-productive pass, allowing thecompound to cool, followed by a mill finish on a two roll mill. For thefirst pass, the mixer speed was adjusted to 85 rpm and a startingtemperature of 150° F. Both the solution Styrenebutadiene rubber (SBR),BUNA® VSL 5228-2 (vinyl content: 52%; styrene content: 28%; TreatedDistillate Aromatic Extract (TDAE) oil content: 37.5 parts per hundredrubber (phr); Mooney viscosity (ML(1+4100°) C):50) obtained commerciallyfrom LANXESS, and butadiene rubber (BR), BUDENE™ 1207 (cis 1,4 content98%; Mooney viscosity (ML(1+4100°) C):55) obtained commercially from TheGoodyear Tire & Rubber Company, polymers were added to the mixer. After30 seconds into the mix cycle half of the test silica and all of theSi-69® Silane (Bis(triethoxysilylpropyl)tetrasulfide, obtainedcommercially from Evonik) was added to the mixer. After another 30seconds into the mix cycle the other half of the test silica as well asthe Vivatec® 500 TDAE processing oil obtained commercially from the H &R Group Inc. was added to the mixer. After another 30 seconds into themix cycle, the ram was raised and the chute swept, i.e., the covering onthe entry chute was raised and any material that was found in the chutewas swept back into the mixer and the ram lowered. After another 30seconds into the mix cycle the combination of Kadox®-720C surfacetreated zinc oxide, obtained commercially from Zinc Corporation ofAmerica, Rubber grade stearic acid, obtained commercially from R.E.Carroll, Stangard Santoflex® 13 antiozonant, described asN-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, obtainedcommercially from Harwick Standard and SUNPROOF® Improved antiozonanthydrocarbon wax obtained commercially from ADDIVANT™ USA, LLC. was addedto the mixer. After another 30 seconds, the ram was raised and the chuteswept. From 150 seconds into the mix cycle forward the mixer speed wasadjusted to reach and/or maintain a temperature of 338° F.+/−5° F. forover a 390 second timeframe. The first pass was dropped at a temperatureof 338° F.+/−5° F. after approximately 540 seconds of total mix time.

Rubber Makers sulfur (“RM sulfur”), 100% active, obtained commerciallyfrom Taber, Inc., the Santocure CBS,n-cyclohexyl-2-benzothiazolesulfenamide obtained commercially fromHarwick Standard, and the diphenylguanidine, obtained commercially fromHarwick Standard Inc., were blended into the cooled first passMasterbatch on a two-roll rubber mill. Milling was done forapproximately 5 minutes performing 5 side cuts and 5 end passes.

TABLE 3 Model Passenger Tread Formulation I EXAMPLE PASS 1 A.1A A.2AA.3A Mix Program Step Additions (PHR) (PHR) (PHR) POLYMERS VLS 5228-2130.10 130.10 130.10 BR 1207 25.00 25.00 25.00 SILICA of Silica 40.000.0 0.0 Example CE-A.1 SILICA of Treated Silica 0.0 40.0 0.0 Example A.2SILICA of Treated Silica 0.0 0.0 40.0 Example A.3 SILANE Si-69 7.00 7.007.00 SILICA of Silica 40.00 0.0 0.0 Example CE-A.1 SILICA of TreatedSilica 0.0 40.0 0.0 Example A.2 SILICA of Treated Silica 0.0 0.0 40.0Example A.3 VIVATEC 500 5.00 5.00 5.00 OTHER Zinc Oxide (720 C.) 2.502.50 2.50 Stearic Acid 1.00 1.00 1.00 SANTOFLEX 13 2.00 2.00 2.00SUNPROOF Improved 1.50 1.50 1.50 Subtotal wt: 227.10 227.10 227.10 STOCKSHEETED OFF AT APPROXIMATELY .085″ STOCK WAS COOLED BEFORE MILL FINISHAFTER A MINIMUM OF ONE HOUR REST Weight, MILL FINISH Additions gramsMasterbatch (from Pass 1) 227.10 227.10 227.10 RM Sulfur 1.40 1.40 1.40SANTOCURE CBS 1.70 1.70 1.70 DPG 2.0 2.0 2.0 18 END PASSES Total PHR:232.20 232.20 232.20

Stress/Strain test specimens were cured for 30″ at 150° C. while allother test specimens were cured for 40″ at 150° C. Specimen preparationand testing were performed using the procedures and equipment shown inpart 2. The compound performance properties are shown in Table 4.

TABLE 4 Model Passenger Tread Formulation Results Example CE-A.1A A.2AA.3A Anhydride Treatment None Succinic Allyl succinic Descriptionanhydride anhydride Si-69 Addition (PHR) 7.0 7.0 7.0 Mooney Viscosity,ML (1 + 4) 82.1 67.7 67.3 Stress Strain 300/100% Modulus ratio 5.4 5.76.0 DIN Abrasion Loss, mm³ 144 140 138 ARES -Temperature Sweep, 1 Hz, 2%strain Tan (δ) @ 60° C. 0.053 0.055 0.059 @ 0° C. 0.323 0.304 0.313Delta: 0° C.-60° C. 0.270 0.249 0.254 ARES - Strain Sweep, 30° C., 1 HzΔ G′, 0.5%-16% 0.403 0.388 0.342

It can be seen that the inventive silicas reduce the Mooney viscosity,ML (1+4) with respect to the comparative control. Furthermore, similaror reduced wear is observed as well as a small increase in thereinforcement ratio (300/100% Modulus). Other important properties arenot negatively affected by the treatment.

Although the present invention has been described with references tospecific details of certain embodiments thereof, it is not intended thatsuch details should be regarded as limitations upon the scope of theinvention except in so far as they are included in the claims.

What is claimed is:
 1. A process for producing treated fillercomprising: (a) treating a slurry comprising untreated filler whereinsaid untreated filler has not been previously dried, with a treatingcomposition comprising a treating agent, thereby forming a treatedfiller slurry; and (b) drying said treated filler slurry to producetreated filler, wherein said treating agent comprises at least one of ananhydride, a cyclic imide, and a derivative thereof.
 2. The process ofclaim 1, wherein said untreated filler is chosen from aluminum silicate,silica gel, colloidal silica, precipitated silica, and mixtures thereof.3. The process of claim 1, wherein the filler comprises precipitatedsilica.
 4. The process of claim 1, wherein the treating agent comprisesa ring opened product of the cyclic imide and/or a cyclic anhydride. 5.The process of claim 1, wherein the treating agent comprises a salt ofthe anhydride and/or the cyclic imide.
 6. The process of claim 1,wherein the treating agent comprises at least one of benzoic anhydride,acetic anhydride, maleic anhydride, succinic anhydride, maleimide,succinimide, and/or derivatives thereof.
 7. The process of claim 1,wherein the anhydride, the cyclic imide, and/or derivative thereof eachindependently further comprises at least one group having acarbon-carbon double bond.
 8. The process of claim 1, wherein thetreating composition further comprises an organosilane coupling agentrepresented by formula (II):(R₁)_(a)(R₂)_(b)SiX_(4-a-b)  (II), wherein each R₁ is independently ahydrocarbyl group comprising 1 to 36 carbon atoms and a functionalgroup, wherein the functional group of the hydrocarbyl group is vinyl,allyl, hexenyl, epoxy, glycidoxy, (meth)acryloxy, sulfide, isocyanato,polysulfide, mercapto, or halogen; each R₂ is independently ahydrocarbyl group having from 1 to 36 carbon atoms or hydrogen, X isindependently halogen or alkoxy having 1 to 36 carbon atoms; a is 0, 1,2, or 3; b is 0, 1, or 2; (a+b) is 1, 2, or 3; provided that when b is1, (a+b) is 2 or
 3. 9. The process of claim 8, wherein the treatingcomposition further comprises an organosilane different from theorganosilane represented by formula (II).
 10. The process of claim 1,wherein the treating composition further comprises a coupling agentcomprising an organosilane selected from the group consisting of(4-chloromethyl-phenyl)trimethoxysilane,(4-chloromethyl-phenyl)triethoxysilane,[2-(4-chloromethyl-phenyl)-ethyl]trimethoxysilane,[2-(4-chloromethyl-phenyl)-ethyl]triethoxysilane,(3-chloro-propenyl)-trimethoxysilane,(3-chloro-propenyl)-triethoxysilane, (3-chloro-propyl)-triethoxysilane,(3-chloro-propyl)-trimethoxysilane, trimethoxy-(2-p-tolyl-ethyl)silaneand triethoxy-(2-p-tolyl-ethyl)silane, and combinations thereof.
 11. Theprocess of claim 1, wherein the treatment composition further comprisesa non-coupling agent that is different from the treating agent andwherein the non-coupling agent that is different from the treating agentis one or more of a biopolymer, fatty acid, organic acid, polymeremulsion, polymer coating composition, and combinations thereof.
 12. Theprocess of claim 1, wherein the treatment composition further comprisesa non-coupling agent selected from an anionic surfactant, a nonionicsurfactant, an amphoteric surfactant, and combinations thereof, presentin an amount of from greater than 1% to 25% by weight based on theweight of untreated filler.
 13. The process of claim 1, wherein thetreated filler comprises treated precipitated silica; and the treatingcomposition further comprises: (i) at least one coupling agent, and (ii)a non-coupling agent chosen from anionic, nonionic and/or amphotericsurfactants, which is present in an amount of from greater than 1% to25% by weight based on the weight of untreated filler.
 14. A treatedfiller produced by the process of claim
 1. 15. A rubber compositioncomprising the treated filler produced by the process of claim
 1. 16.The rubber composition of claim 15, wherein the rubber compositioncomprises natural rubber.
 17. The rubber composition of claim 15,wherein the rubber composition is a rubber compounding master batch. 18.A process for producing treated precipitated silica comprising: (a)combining an alkali metal silicate and an acid to form a slurrycomprising untreated silica, wherein said untreated silica has not beenpreviously dried; (b) treating said slurry with a treating compositioncomprising a treating agent, thereby forming a treated slurry; and (c)drying said treated slurry to produce a treated precipitated silica,wherein said treating agent comprises at least one of an anhydride, acyclic imide, and a derivative thereof.
 19. The process of claim 18,wherein the treating agent comprises a ring opened product of the cyclicimide and/or a cyclic anhydride.
 20. The process of claim 18, whereinthe treating agent comprises a salt of the anhydride and/or the cyclicimide.
 21. The process of claim 18, wherein the treating agent comprisesat least one of benzoic anhydride, acetic anhydride, maleic anhydride,succinic anhydride, maleimide, succinimide, and/or derivatives thereof.22. The process of claim 18, wherein the anhydride, the cyclic imide,and/or derivative thereof each independently further comprises at leastone group having a carbon-carbon double bond.
 23. The process of claim18, wherein said alkali metal silicate comprises aluminum silicate,lithium silicate, sodium silicate, and/or potassium silicate.
 24. Theprocess of claim 18, wherein the treating composition further comprisesa coupling agent comprising an organosilane, selected from the groupconsisting of (4-chloromethyl-phenyl)trimethoxysilane,(4-chloromethyl-phenyl)triethoxysilane,[2-(4-chloromethyl-phenyl)-ethyl]trimethoxysilane,[2-(4-chloromethyl-phenyl)-ethyl]triethoxysilane,(3-chloro-propenyl)-trimethoxysilane,(3-chloro-propenyl)-triethoxysilane, (3-chloro-propyl)-triethoxysilane,(3-chloro-propyl)-trimethoxysilane, trimethoxy-(2-p-tolyl-ethyl)silaneand triethoxy-(2-p-tolyl-ethyl)silane, and combinations thereof.
 25. Theprocess of claim 18, wherein the treatment composition further comprisesa non-coupling agent selected from an anionic surfactant, a nonionicsurfactant, an amphoteric surfactant, and combinations thereof, presentin an amount of from greater than 1% to 25% by weight based on theweight of untreated filler.
 26. A process for producing treatedprecipitated silica comprising: (a) combining an alkali metal silicateand an acid to form an untreated slurry comprising untreated silica,wherein said untreated silica has not been previously dried; (b) dryingthe untreated slurry to produce dried precipitated silica; (c) formingan aqueous slurry of the dried precipitated silica with a treatingcomposition comprising a treating agent, and, optionally, a couplingagent and/or, optionally, a non-coupling agent to form a treatedprecipitated silica slurry; and (d) drying the treated precipitatedsilica slurry to produce a dried treated precipitated silica, whereinsaid treating agent comprises at least one of an anhydride, a cyclicimide, and a derivative thereof.
 27. The process of claim 26, whereinthe treating agent comprises a ring opened product of the cyclic imideand/or a cyclic anhydride.
 28. The process of claim 26, wherein thetreating agent comprises a salt of the anhydride and/or the cyclicimide.
 29. The process of claim 26, wherein the treating agent comprisesat least one of benzoic anhydride, acetic anhydride, maleic anhydride,succinic anhydride, maleimide, succinimide, and/or derivatives thereof.30. The process of claim 26, wherein the anhydride, the cyclic imide,and/or derivative thereof each independently further comprises at leastone group having a carbon-carbon double bond.
 31. A treated precipitatedsilica prepared by the method of claim
 26. 32. A rubber compositioncomprising the treated precipitated silica produced by the process ofclaim 26.